Apple is reaching out to owners of the iPhone 5s because of a manufacturing issue that could result in reduced battery life.

The problem is only affecting a "very limited" number of iPhone 5s devices, Apple said. In addition to reduced battery life, the issue could also could cause longer charging times.

"We are reaching out to customers with affected phones and will provide them with a replacement phone," an Apple spokeswoman said via email. Apple didn't elaborate on how many phones were affected and what had caused the problem.

The company, however, isn't alone in struggling with battery-related problems. Earlier this month Samsung Electronics offered some owners of its Galaxy S4 replacement batteries because the existing ones weren't able to stay charged. The company said that a limited number of users were affected, but just like Apple it didn't elaborate on the actual number.

The iPhone 5s was launched on Sept. 10 and has a 64-bit processor, a new 8-megapixel camera and a fingerprint sensor. Apple then managed to sell a record-breaking nine million units of the iPhone 5s and fellow newcomer iPhone 5c three days after their Sept. 20 launch.

During the third quarter Apple sold 33.8 million iPhones, compared to 26.9 million during the same period in 2012. But that wasn't enough to keep up with the overall growth of the smartphone market, so its unit market share dropped from 15.6 percent to 13.4 percent, according to research from Strategy Analytics. All the other vendors in the top five -- Samsung, Huawei Technologies, LG Electronics and Lenovo -- grew their respective share.